Interface Engineering for Scalable and Flexible Optoelectronics

Abstract

Next-generation photovoltaics provide lightweight and flexible energy solutions ideal for integration into urban, mobile, and aerospace environments. Yet, their performance and reliability remain limited by interfacial instabilities that intensify during the transition from laboratory-scale devices to large-area modules. This thesis establishes a unified framework of holistic interface engineering grounded in rational molecular and precursor design. Moving beyond empirical surface treatments, it presents a chemistry-driven blueprint for addressing the root causes of inefficiency, instability, and mechanical fragility—from buried contacts to top electrodes. Theme I develops a chemical foundation for scalable organic photovoltaics by systematically overcoming processing and functional challenges at the top interface. An anion-induced catalytic conversion for metal oxides and an in situ doping strategy for conducting polymers were devised to enable fully solution-processed, thermally compatible architectures. The elimination of high-temperature annealing preserves the integrity of underlying organic photoactive layers and aligns with high-throughput, continuous manufacturing. These advances culminate in large-area, encapsulated organic solar modules that exhibit prolonged operational stability, confirming both the scalability and practicality of the proposed interfacial design. Theme II extends these design principles to high-performance perovskite systems through a multi-tiered, chemistry-based approach addressing both buried and top interfaces. At the buried interface, a photocatalytic precursor-purification route removes residual impurities during metal-oxide nanoparticle synthesis, producing a structurally uniform nickel-oxide scaffold. At the top interface, a rationally designed asymmetric π-conjugated molecule serves as a molecular bridge, reconciling the long- standing trade-off between defect passivation and charge transport. This synergistic atoms-to-module framework yields perovskite solar cells with certified efficiencies of 26.94% at the small-cell scale and 24.23% for 25 cm² modules, maintaining outstanding stability under simultaneous thermal, operational, and mechanical stress. Collectively, the findings demonstrate that precise chemical control—from precursor purity to molecular architecture—governs the macroscale performance of next-generation photovoltaics. The results establish interface engineering as a decisive pathway toward scalable, flexible, and durable optoelectronic systems, aligning the molecular origins of stability and performance with the practical demands of sustainable energy technologies.